A compressor, such as a scroll compressor, generally includes a pumping device for pumping lubricating oil to lubricate and cool various components.
FIG. 1 shows a longitudinal sectional view of a conventional scroll compressor. The scroll compressor 100 generally includes a housing 110, a top cover 112 provided at one end of the housing 110, a bottom cover 114 provided at the other end of the housing 110, and a partition plate 116 which is provided between the top cover 112 and the housing 110 to divide an inner space of the compressor into a high pressure side and a low pressure side. The high pressure side is formed between the partition plate 116 and the top cover 112, and the low pressure side is formed among the partition plate 116, the housing 110 and the bottom cover 114. An inlet 118 for inflowing fluid is provided at the low pressure side, and an outlet 119 for discharging compressed fluid is provided at the high pressure side. In the housing 110, a motor 120 including a stator 122 and a rotor 124 is provided. A driving shaft 130 is provided in the rotor 124 to drive a compression mechanism including a fixed scroll 150 and a movable scroll 160. The driving shaft 130 has an upper end supported by a main bearing housing 140 and a lower end supported by a lower bearing 142. The upper end of the driving shaft 130 is provided with an eccentric crank pin 132. The eccentric crank pin 132 is fitted into a hub 162 of the movable scroll 160. When the motor 120 is driven, the eccentric crank pin 132 drives the movable scroll 160 to orbit relative to the fixed scroll 150 (that is, a central axis of the movable scroll 160 rotates about a central axis of the fixed scroll 150, but the movable scroll 160 itself will not rotate about the central axis thereof), thus compressing fluid between the fixed scroll 150 and the movable scroll 160.
In the driving shaft 130, provided are a central hole 134 extending upwards along a longitudinal direction from the lower end of the driving shaft 130, and an eccentric hole 136 which is offset relative to the central hole 134 and extends to an end of the eccentric crank pin 132. In the lower end of the driving shaft 130, a rotor pump 170 is provided as an oil pumping device. When the scroll compressor 170 operates, the rotor pump 170 sucks lubricating oil from an oil sump at the bottom of the housing 110 and pumps it into the central hole 134 of the driving shaft 130. Then, the lubricating oil enters into the eccentric hole 136 in communication with the central hole 134, and further moves upwards under the centrifugal force of the driving shaft 130 to reach the end of the eccentric crank pin 132. The lubricating oil discharged from the eccentric crank pin 132 flows downwards under the gravity and splashes under the action of moving components so as to lubricate and cool the components in the compressor.
Constructions and operation principles of other components of the compressor 100 can refer to, for example, the patent applications US2009/0068044A1, US2009/0068048A1, US2009/0068045A and the like, which are incorporated herein by reference in their entirety.
Construction and operation principle of the rotor pump 170 is described with reference to FIGS. 2 to 4C. However, it is noted that, the rotor pump 170 shown in FIGS. 2 to 4C and described below does not necessarily constitute the prior art with respect to the present application.
FIG. 2 shows an exploded perspective view of the rotor pump 170; FIG. 3 shows a longitudinal sectional view of the rotor pump 170 after being assembled; and FIGS. 4A, 4B and 4C show an operation process of the rotor pump.
The rotor pump 170 mainly includes a housing 172, a pump body 174, a pump wheel 176, a sealing plate 178, a covering plate 180 and a thrust sheet 182. The pump body 174 is provided inside the housing 172 and has a substantially cylindrical inner circumference. The pump wheel 176 is provided inside the pump body 174 and has a substantially cylindrical outer circumference. A recess 1741 is provided in the inner circumference of the pump body 174, and a protrusion 1761 is provided on the outer circumference of the pump wheel 176. In the central portion of the pump wheel 176, a driving hole 1762 driven by an eccentric pin 138 (see FIG. 1) on the lower end of the driving shaft 130 is provided. The protrusion 1761 of the pump wheel 176 is fitted in the recess 1741 of the pump body 174. Thus, when the eccentric pin 138 of the driving shaft 130 is inserted into the driving hole 1762 of the pump wheel 176 to drive the pump wheel 176, the protrusion 1761 of the pump wheel 176 can slide in the recess 1741 of the pump body 174 and pivots about a connect point between the protrusion 1761 and the recess 1741. During rotation of the pump wheel 176, a contact point between the outer circumference of the pump wheel 176 and the inner circumference of the pump body 174 moves along a direction in which the pump wheel 176 is driven, so that the volume of an operating cavity formed between the pump wheel 176 and the pump body 174 is gradually changed, thereby pumping fluid, which will be described below with reference to FIGS. 4A to 4C.
A sealing plate 178 is provided at one side of the pump wheel 176. Also, referring to FIG. 4A, an inlet 1781 for inflowing fluid and an outlet 1782 for discharging fluid are provided at positions on the sealing plate 178 that substantially correspond to the inner circumference of the pump body 174. The inlet 1781 and the outlet 1782 are provided on the two opposite sides of the recess 1741 and near the recess 1741. The sealing plate 178 is further provided with a central through hole 1783 at a central portion thereof. A covering plate 180 is provided on one side of the sealing plate 178 and is assembled with the housing 172. The covering plate 180 is provided therein with a through hole 1801 in communication with the inlet 1781 of the sealing plate 178 for introducing external fluid and a guiding groove 1802 which communicates the outlet 1782 with the central through hole 1783 of the sealing plate 178. The thrust sheet 182 is provided on the other side of the pump wheel 176 for preventing the pump wheel 176 from displacing axially.
The operation principle of the rotor pump 170 shown in FIGS. 2 to 3 is described with reference to FIGS. 4A to 4C. It is assumed that the pump wheel 176 is driven along a direction indicated by arrows in the figures. An operation cavity of the rotor pump is defined between the inner circumference of the pump body 174 and the outer circumference of the pump wheel 176. Specifically, the operation cavity in communication with the inlet 1781 of the sealing plate 178 is referred to as a suction cavity 192, and the operation cavity in communication with the outlet 1782 of the sealing plate 178 is referred to as a discharge cavity 194. The suction cavity 192 and the discharge cavity 194 are separated from each other by a contact point CP between the pump body 174 and the pump wheel 176
During normal operation, the external fluid flows in the suction cavity 192 through the through hole 1801 in the covering plate 180 and the inlet 1781 of the sealing plate 178, and the compressed fluid flows through the outlet 1782 in the sealing plate 178 and the guiding groove 1802 in the covering plate 180 and finally is discharged through the central through hole 1783 in the sealing plate 178, for example, into a through hole provided in the driving shaft 130.
In the state shown in FIG. 4A, the suction cavity 192 is small, and the discharge cavity 194 is big. As shown in FIGS. 4B and 4C, as the pump wheel rotates along the direction indicated by the arrow, the suction cavity 192 gradually increases to suck fluid; and the discharge cavity 194 gradually decreases so as to urge the fluid to be discharged through the outlet 1782.
However, the above rotor pump has a complex structure and has a number of components. Thus, it is still possible to improve the rotor pump to further simplify the structure of the rotor pump, reduce the number and the volume of the components thereof, and reduce the cost thereof.